This invention relates to flexible bulk containers.
Such containers may be used in the storage and transport of materials in granular, powder and other particulate form, such as chemicals, foodstuffs, cement and so forth. The containers are generally in the form of large bags or sacks. They are often required to carry loads of up to one ton or more, and there should desirably be a considerable safety margin above this working load.
The containers are frequently made from woven fabric, for example woven polypropylene or another suitable synthetic material. In many instances there will be seams between adjacent portions of the container and it has been found that in use these can become regions of high stress concentration so that there is an increased tendency of the fabric to tear adjacent the seams. It is also known to attach lifting loops or the like to the main body of the container, and the points of attachment may similarly become regions of high stress concentration.
Various methods have been proposed for reinforcing a container in regions of potentially high stress concentrations, but many of these proposals involve the use of additional reinforcing material and an increased number of manufacturing steps. This may increase the time and cost of production, which can be undesirable, particularly if the containers are intended to be disposable.